Hi this first build is the best and most effective build when playing as the main tank on your team as opposed to the off-tank or damage-tank.

Talent Selection

Tier 1: You can pick either 'Together we are strong' or 'Maximum charge'. If you can keep your charge level high and are a confident/ good enough player as Zarya, then I would recommend 'Maximum charge' as you'll be able to make full effect of this telent.
But if you're not as confident that you'll be able to pull that off, or simply want the other talent (doesn't mean you are bad), then you can pick 'together we are strong' which provides an extra boost with getting your energy levels higher which then allows you to do more damage.
'Together we are strong' is the talent that will come into play much more often during the match as it becomes relevant every single time you use your shield and will be more reliable as with the other talent, it's not guarenteed you'll be able to reach those energy levels that often in the match.

Tier 2: This is a much more simple choice as 'give me twenty' allows you to really increase the amount of damage you can shield on your allies while also reducing the cooldown so that you can use it more often, further increasing how much you can shield. You could also choose 'I am the strongest' which allows you to shield more damage on yourself but the amount is much less tha with the other talent, and also means you don't have the more useful increase you can shield your allies.

Tier 3: All of this tiers talent are damage boosting except for 'hit me' which grants a massive increase in energy gained when taking damage on either of your shield abilities. By choosing this talent, it means you can do more damage while also being able to use your abilities more often which in turn will mean more tanking and more energy to perpetually do more damage and cast more abilities throughout the match.

Ultimate abilities: You can choose either of these but you should decide depending on the enemy team and your own teammates heroes.
Graviton surge: use this ability when you're against a team that groups up more often as this will stun and disable all of them in a small bunch allowing your team to freely attack them without the enemy being able to escape. Secondly, this ability is very good when your team has lots of aoe damage so look out for who your teammates are before deciding.

Expulsion zone: this ability literally does the opposite of graviton surge by pushing any enemies caught in it away from the zone it was cast in, separating the enemy and not allowing them to move through that zone until it runs out. This ability is great to use when you want to pick off enemies by separating them from the rest of the team, or for making the enemy panic and mess up. Secondly, this ability allows you to zone out an area which can be very useful for making space between you and the enemy whether you're capturing an objective, or trying to escape death.
Expulsion zone is great to use in narrow corridors or chokepoints as it can completely block the enemy from either escaping or entering the area or can even be used to split the team in half so that you can kill them more easily.

Tier 5: In order to best increase your endurance and allow you to be more sturdy and tanky, picking 'endurance training is a no brainer as the other abilities are all very situational, meanwhile when you have high energy, not only will you be able to do much more damage, but with 'endurance training' you'll be able to completely change the tide of a battle.

Tier 6: Allows you to shield 2 people instead of one allowing you to shield for twice as much damage.

Tier 7: Being able to reset cooldowns of your shields allows you to cast them twice over as quickly as you want in order to shield for twice as much damage.

The damage tank build greatly focuses on getting talents for the particle cannon but also a couple of tanking talents in order to greatly increase the amount of damage you can do while also remaining tanky.

Talent selection

Tier 1: This first talent is a quest which when finished, will lower the cooldown of particle cannon while also increasing its hit area allowing you to cast it more often and for it to hit more easily.

Tier 2: 'give me twenty' is simply the best talent in this tier and is chosen for the same reasons as in the first build.

Tier 3: This talent rewards players who are accurate with the shots as when enemies are hit in the centre of the ability radius, damage is greatly increased, encouraging you to be as accurate as possible.

Tier 4: Zaryas basic attack and particle cannon are both aoe attacks so by far the best option for which ulti to pick is graviton surge so you can bunch up the energy and destroy them with your aoe.

Tier 5: 'endurance training' is again just the best talent in its tier as 'give me twenty' is

Tier 6: 'plasma shock' allows you to slow down the enemy when they are hit with your particle cannon. This has alot of utlity as it can be used to chase the enemy down, slow them from chasing you or your damaged teammates, or so they are an easier target to hit for your cannon or your allies.

Tier 7: This last talent is fantastic because by returning all your cannons charges all at the same time as soon as you run out, you will be able to spam it as often as you like, being able to maximise your damage while also constantly suppressing the enemy with intimidation and the slowing talent you got at tier 6.